Year: 2026
Type: preprint
Abstract: Phosphatidylinositol 3-kinase–related kinases (PIKKs), including ATM, ATR, DNA-PKcs, SMG1, TRRAP and mTOR, are regulators of gene expression, DNA damage response and metabolism. Their maturation depends on R2TP, a co-chaperone complex comprising the RUVBL1/2 AAA+ ATPase, RPAP3 and PIH1D1. While small-molecule RUVBL1/2 inhibitors have shown promise in cancer models, the presence of RUVBL1/2 in other complexes raises concerns about specificity. Here, we identified the RUVBL1/2-RPAP3 interface as a vulnerability, exploiting it using de novo designed protein binders that occupy the RPAP3-binding site. These subnanomolar-affinity binders dismantle R2TP, depleting levels of all PIKKs while sparing other RUVBL1/2-containing complexes, including chromatin remodelers INO80, SRCAP and TIP60. CryoEM, proteomic, biochemical and cellular analyses revealed that these binders outcompete RPAP3, trapping RUVBL1/2 in a catalytically inactive conformation. Our findings establish selective disruption of R2TP by artificial proteins as a strategy to control PIKK abundance.
Language: English
Topic: Heat shock proteins research
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: green
Funders: Stop Cancer, Diamond Light Source, European Commission, Eusko Jaurlaritza, Euskal Herriko Unibertsitatea, Ministerio de Ciencia e Innovación, HORIZON EUROPE Framework Programme, Instituto de Salud Carlos III, European Regional Development Fund, Agencia Estatal de Investigación, NextGenerationEU
Awards: G1188944981, G1204740081, G1710482639, G1719462714, G1855990336, G2309174360, G280048558, Providing cutting edge cancer research services across Europe, G318412399, G348919436, G3518538256, G363809202, G4033406476, G410571670, G430777504, G451917667, G5421974903, G554358111, G5943232429, G5967599077, G631184005, G6520718613, G6619188030, G745419941, G7613964388, G8546142835, G8911147183
OpenAlex ID: W7224078872